test: restructure dir layout

Attempt to clarify the structure of our tests. Each test case is now
encapsulated in a script in `test/cases`. Each of these scripts should
be runnable on a pristine machine and be independent of each other. It
is up to the test-orchestractor to decide if they should be run
consequtively instance, or in parallel on separate instances. Each
script can execute several tests and call whatever helper binaries
is desired. However, each case should be assumed to always run as one.

internal/distro/distro_test.go

@@ -15,7 +15,7 @@ import (
 func TestDistro_Manifest(t *testing.T) {
 	distro_test_common.TestDistro_Manifest(
 		t,
-		"../../test/data/cases/",
+		"../../test/data/manifests/",
 		"*",
 		fedora32.New(), fedora33.New(), rhel8.New(),
 	)

internal/distro/fedora32/distro_test.go

@@ -288,7 +288,7 @@ func TestImageType_BasePackages(t *testing.T) {
 }
 
 func TestDistro_Manifest(t *testing.T) {
-	distro_test_common.TestDistro_Manifest(t, "../../../test/data/cases/", "fedora_32*", fedora32.New())
+	distro_test_common.TestDistro_Manifest(t, "../../../test/data/manifests/", "fedora_32*", fedora32.New())
 }
 
 func TestFedora32_ListArches(t *testing.T) {

internal/distro/fedora33/distro_test.go

@@ -294,7 +294,7 @@ func TestImageType_BasePackages(t *testing.T) {
 }
 
 func TestDistro_Manifest(t *testing.T) {
-	distro_test_common.TestDistro_Manifest(t, "../../../test/data/cases/", "fedora_33*", fedora33.New())
+	distro_test_common.TestDistro_Manifest(t, "../../../test/data/manifests/", "fedora_33*", fedora33.New())
 }
 
 func TestFedora33_ListArches(t *testing.T) {

internal/distro/rhel8/distro_test.go

@@ -347,7 +347,7 @@ func TestImageType_BasePackages(t *testing.T) {
 }
 
 func TestDistro_Manifest(t *testing.T) {
-	distro_test_common.TestDistro_Manifest(t, "../../../test/data/cases/", "rhel_8*", rhel8.New())
+	distro_test_common.TestDistro_Manifest(t, "../../../test/data/manifests/", "rhel_8*", rhel8.New())
 }
 
 func TestRhel8_ListArches(t *testing.T) {